1. Technical field
This application relates to surgical instruments for joining tissue, and more particularly, to surgical instruments that are pull activated for sequentially applying a plurality of surgical fasteners to body tissue and to electrosurgical instruments that are configured to sever tissue after tissue has been electrosurgically treated.
2. Background of Related Art
Surgical instruments wherein tissue is first grasped or clamped between opposing jaw structure and then joined by surgical fasteners, or other suitable means, are well known in the art. Instruments for this purpose can include two elongated members which are respectively used to capture or clamp tissue. Typically, such surgical instruments include a shaft extending from a handle and/or trigger assembly, an end effector assembly, which includes an anvil assembly and a cartridge assembly for supporting a plurality of surgical fasteners, an approximation mechanism for approximating the anvil and cartridge and anvil assemblies, and an actuation assembly for ejecting the surgical fasteners from the cartridge assembly. In some instances, the surgical instrument may be adapted to connect to a loading unit (e.g., disposable loading unit) that includes an end effector assembly, which includes an anvil assembly and a cartridge assembly for supporting a plurality of surgical fasteners. Typically, the actuation assembly is operatively coupled to a sled, cam or wedge in operative mechanical communication with the cartridge assembly. During a firing sequence of the surgical instruments, the sled is translated into contact with a pusher associated with a surgical fastener causing the surgical fastener to eject from the cartridge assembly and into the anvil assembly such that a surgical fastener line may be formed within tissue.
Electrosurgical instruments (e.g., electrosurgical forceps) are well known in the medical arts and can include a handle, a shaft and an end effector assembly, which includes jaw members operatively coupled to a distal end of the shaft, that is configured to manipulate tissue (e.g., grasp and seal tissue). Electrosurgical forceps utilize both mechanical clamping action and electrical energy to effect hemostasis by heating the tissue and blood vessels to coagulate, cauterize, seal, cut, desiccate, and/or fulgurate tissue. The electrosurgical forceps may include a knife blade or cutter which may be configured to translate within a knife channel or slot operatively associated with one or both of the jaw members such that after the tissue has been electrosurgically treated (e.g., sealed), tissue may be effectively severed.
In some instances, it may prove advantageous to bend or articulate the shaft of the surgical instruments (e.g., during a lower anterior resection “LAR” procedure) and/or the electrosurgical forceps (e.g., during an electrosurgical tissue sealing procedure). When the shaft of the surgical instruments is bent or articulated, there may exist practical challenges associated with a translation force required to translate the sled along the shaft during the firing sequence. Likewise, when the shaft of the electrosurgical forceps is bent or articulated, there may exist practical challenges associated with a translation force required to translate the knife blade within the knife slot after tissue has been electrosurgically treated. When the shaft of the surgical fastener applying instrument is articulated, a force is required to close the anvil assembly and cartridge assembly onto tissue, translate a knife and/or fire or deploy the surgical fastener.